• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.907-916
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• 2018

This study presents a methodology that can integrate the information generated by the Busan taxi DTGs and Tachometers. Utilizing the results by the methodology, travel patterns of taxi users were analyzed. Also to verify the reliability of the methodology was conducted by comparing its results with those of O-D information of the National Transportation DB (KTDB). Despite the limited number of samples. the results of this study showed that DTG data, which can reflect changes in status and conditions in real time, can be used as a replacement for KTDB. It is expected that the results generated by the suggested methodology can be useful for developing and executing desirable taxi related policies.

• Journal of KIISE:Software and Applications
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• v.26 no.2
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• pp.251-262
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• 1999

SCR 방법론은 고 신뢰도를 요구하는 시스템 개발을 위해 사용되는 요구사항의 정형적 명세의 하나로 , 오랜 역사와 많은 응용 사례를 가지고 있다. 이 방법론에 따라 사용자가 요구사항을 명세했을 때 그것을 어떻게 정확하게 구현할 수 있는지가 중요한 문제가 된다. 본 논문에서는 SCR로 작성된 명제를 그 의미를 보전하는 구현언어로 자동으로 변환시키는 방법을 제시한다. SCR 명제가 가지는 자료흐름언어와의 유사성을 이용하기 위해, 구현언어로, 동기적 자료흐름 언어인 LUSTRE를 선택했고, 그 변환 과정을 제시했다. 제안한 방법의 유용성을 살피기 위해, SCR과 유사한 방법으로 작성된 월성 원자력 발전소의 제 2 정지 시스템의 일부분을 변환하는 실험을 수행, 그 결과를 비교하였다. 정형명제가 도입되어서 사용될 경우 본 연구는 개발의 전체 소요시간을 줄여줄 수 있고 좀 더 신뢰성 있는 결과물을 내는데 도움을 줄 수있다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.605-613
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• 2014

Epistemic uncertainty, the lack of knowledge, is often more important than aleatory uncertainty, variability, in estimating reliability of a system. While the probability theory is widely used for modeling aleatory uncertainty, there is no dominant approach to model epistemic uncertainty. Different approaches have been developed to handle epistemic uncertainties using various theories, such as probability theory, fuzzy sets, evidence theory and possibility theory. However, since these methods are developed from different statistics theories, it is difficult to interpret the result from one method to the other. The goal of this paper is to compare different methods in handling epistemic uncertainty in the view point of calculating the probability of failure. In particular, four different methods are compared; the probability method, the combined distribution method, interval analysis method, and the evidence theory. Characteristics of individual methods are compared in the view point of reliability analysis.

• The Journal of the Korea Contents Association
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• v.18 no.5
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• pp.635-646
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• 2018

This study applied Q methodology to graduate students of food service management department in Seoul to grasp subjective perception of customers using Michelin guide restaurant. Six types of analysis result were obtained. Specifically, the first type (N = 3): Restaurant hygiene-seeking type, the second type (N = 6): Restaurant taste-seeking type, the third type N = 5): Select Restaurant Compare Prices type, 4th type (N = 3): Pursuing taste for restaurant price type, 5th type (N = 2) Restaurant full service select type, and 6th type (N = 3): Restaurant menu configuration Select. In the future, the research on the Michelin guide restaurant will be revised and supplemented with more detailed Q methodological questions and analytical techniques based on many documents and empirical studies, to analyze the various opinions of respondents more concrete and objectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3D
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• pp.347-356
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• 2009

This paper is described clustering analysis of traffic characteristics-based highway classification in order to deviate from methodologies of existing highway functional classification. This research focuses on comparing the clustering techniques performance based on the total within-group errors and deriving the optimal number of cluster. This research analyzed statistical clustering method (Hierarchical Ward's minimum-variance method, Nonhierarchical K-means method) and Kohonen self-organizing maps clustering method for highway characteristic classification. The outcomes of cluster techniques compared for the number of samples and traffic characteristics from subsets derived by the optimal number of cluster. As a comprehensive result, the k-means method is superior result to other methods less than 12. For a cluster of more than 20, Kohonen self-organizing maps is the best result in the cluster method. The main contribution of this research is expected to use important the basic road attribution information that produced the highway characteristic classification.

• Journal of the Korean Geotechnical Society
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• v.18 no.6
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• pp.117-127
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• 2002

A deterministic approach of slope stability, which is generally corresponding to the model of a simple non-linear function for slopes, is problematic in that it does not account the versatile characteristics of ground layers in an effective way. To resolve this problem, this study proposes a new way of analyzing slope stability, so-called “genetic algorithm method, ” so as to reflect some particular conditions pertaining to the grounds under concern. Similarities and differences in slope stability that may exist between homogeneous and multiple ground layers are examined in a competitive manner, Overall, though similarities deemed a little bit salient, the algorithm method turned out to be very applicable to estimating the validity of slope stability. Furthermore, an additional effort to consider long-standing sequential and dynamic changes in both the amount of rainfall and the underground water level is made in order to improve the results.

• Journal of the Korean Geotechnical Society
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• v.18 no.2
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• pp.97-105
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• 2002

Random properties of discontinuities were attributed to the limitation of test methods and lack of obtained data. Therefore, the uncertainties are pervasive and inevitable in rock slope engineering as well as other geotechnical engineering fields. The probabilistic analysis has been proposed to deal properly with the uncertainty. However, previous probabilistic approaches do not take account of the condition of kinematic instability but consider only kinetic instability. In this study, in order to overcome the limitation of the previous studies, the geometric characteristics as well as the shear strength characteristics in discontinuities are taken account into the probabilistic analysis. Then, the new approach to evaluate the probability of failure is suggested. The results of the deterministic analysis which was carried out to compare with the result of the probabilistic analysis, are somewhat different from those of the probabilistic approach. This is because the selected and used data in the deterministic approach do not take account of the random properties of discontinuities.

• Electronics and Telecommunications Trends
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• v.17 no.3 s.75
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• pp.80-86
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• 2002

본 연구는 현재 통신서비스 산업에서 가장 많이 사용하고 있는 5개 예측모형(단순 성장 모형, 단순 Logistic 모형, Gompertz 모형, 확장 Bass 모형, 시간 변동 Bass 모형)을 이용한 초고속 인터넷 가입자에 대한 예측력을 비교 평가하는 데 있다. 예측모형의 추정 방법으로 비선형 회귀방정식(nonlinear regression)을 사용하여 추정의 효율성을 높였다. 예측력 비교분석 기준은 (i) 포화점에 대한 타당성 (ii) 모수에 대한 통계적 유의성 (iii) 실제치 대비 예측치에 대한 AAD 기준을 통하여 예측모형의 예측력을 비교 평가하였다. 본 연구에서 실시한 방법론에 따라 다섯 가지 통신서비스 예측모형의 예측력을 분석한 결과 가장 작은 AAD를 나타낸 예측모형은 Log-Logistic 모형으로 나타났으며, 가장 큰 AAD를 나타낸 예측모형은 단순 Logistic 모형으로 나타났다. 또한 AAD 기준에서 보면 일반적으로 많이 사용하고 있는 Gompertz 예측모형과 Bass 모형 중에서는 Gompertz 예측모형이 더 우월한 것으로 나타났다.

• Broadcasting and Media Magazine
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• v.25 no.2
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• pp.17-26
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• 2020

최근 스마트폰에서의 증강현실, 미적 효과의 증대(예, 라이브 포커싱) 등의 어플리케이션을 제공하기 위해 모바일 기기에서의 3차원 공간 복원 기술에 대한 관심이 증가하고 있다. 소비자들의 요구에 발 맞춰 최근 스마트폰 제조사는 모든 플래그십 모델에 다중 카메라 및 뎁스 센서(거리 측정 센서)를 탑재하는 추세이다. 본 고에서는 모바일 폰에 탑재되고 있는 대표적인 세 축의 뎁스 추정(공간 복원) 방식에 대해 간단히 살펴보고, 최근 심층학습(Deep learning)의 등장으로 기술 발전의 새로운 국면에 접어 든 다중 시점 매칭(Multi-view stereo) 방법에 대해 소개하고자 한다. 심층 신경망이 재조명 받은 2012년 전까지 주류 연구 방향이었던 전통 기하학 기반의 방법에 대한 소개를 시작으로 심층 신경망기반의 방법론으로의 발전된 형태를 살펴본다. 또한, 신경망기반의 방법론은 크게 3 세대로 나누어 각 세대별 특징에 대해 자세히 살펴보고, 다양한 데이터에 대한 실험 결과를 통해 세대별 공간 복원 결과를 비교 분석한다.

• Journal of Korea Water Resources Association
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• v.35 no.5
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• pp.631-638
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• 2002

Stochastic model has been widely used for the forecasting of time series. However, this study tries to perform the precipitation forecasting by fuzzy time series model using fuzzy concept. The published fuzzy based models are used for the forecasting of time series and also we suggest that the combination of fuzzy time series models and neuro-fuzzy system can increase the forecastibility of the models. The precipitation time series in illinois, USA is analyzed for the forecasting by the known fuzzy time series models and the suggested methodology in this study. As a result, we know that the suggested methodology shows more exact results than the known models.